Economy control for split engine



March 29, 1960 s. H. MICK 2,930,368

ECONOMY CONTROL FOR SPLIT ENGINE Filed Oct. 31, 1958 2 Sheets-Sheet 1 I IN VEN T OR.

March 29, 1960 s. H. MICK 2,930,368

ECONOMY CONTROL FOR SPLIT ENGINE Filed Oct. 31, 1958 2 Sheets-Sheet 2 Q) 9/2 W W INVENTOR.

A TTOP/VL'Y ECONOMY CONTROL FOR SPLIT ENGINE Application October 31, 1958, Serial No. 771,073

4 Claims. (Cl. 123-127) The present invention relates to an engine control system in which it is possible to operate the engine on less than all of the cylinders under normal or light load conditions but in which full engine operation is possible when the engine load exceeds a given value. The present invention is an improvement over copending application Serial No. 608,828 Dolza, filed September 10, 1956, now Patent No. 2,875,742.

As explained in the aforenoted copending application, it has been found that considerable economies can be realized when it is possible to resort to split engine operation, for example, being able to operate an eight cylinder engine on four cylinders under moderate load conditions. The economy is effected by the fact that individual cylinder efiiciency is increased when the individual cylinder load is increased during split engine operation in contrast to reduced cylinder loads as occurs with full engine operation during light or moderate load conditions.

It is an inherent characteristic of an internal combustion engine to be most efficient under high load conditions. This is attributable to the quantity of air fed to the cylinders. Maximum air is supplied to the cylinders when the throttle is open, indicative of high load, therefore, more air may be compressed in turn increasing the compression ratio. Since engine efficiency increases with compression pressure and compression pressure increases withcylinder load, the desirabilityof split or part cylinder engine operation as a means for maintaining high cylinder loads becomes apparent.

"Split engine operation has long been recognized as a theoretically desirable goal. However, the general complication of mechanisms which have been developed to achieve this type of operation have thus far precluded its commercial feasibility. The present invention relates to a greatly simplified split engine-control system which has been operated over a considerable period of time and has proved to be most satisfactory in operation.

The invention is illustrated with an eight cylinder although it is apparent that it may be applied to enginesv having any number of cylindersin excess of one. Separate air intake passages, throttles and manifolds are provided for the active and inactive cylinders.

It is apparent that alternate firing cylinders should be selected for active or inactive cylinders. In other words, a normal firing order for an eight cylinder engine might be 1-8--4-3- -6'--57-2. The active cylinder group nited States Patent O In 'generaLithe operation of the split engine control 2,930,368 Patented Mar. 29, 1960 ICC cylinders. At the same time fuel flow to the inactive nozzles is also cut off.

Contemporaneously with the opening of the inactive throttle and the cutting off of fuel flow to the inactive nozzles, means is provided for shifting an accelerator pedal controlled throttle linkage to a position increasing the opening of the active throttle beyond the amount which would otherwise exist during eight cylinder engine operation. This latter adjustment of the active throttle during four'cylinder operation as well as its corollary in which the active throttle isrmoved towards a more closed position when eight cylinder operation is in effect necessary in order to provide a smooth transition between four and eight cylinder engine operation. latter is necessaryin order to make the transition at sub stantially constant engine torque.

The present invention is also an improvement over copending application Serial No. 736,915 Mick, filed May 21, 1958. The improvement consists of the addition of jet or orifice means which further improve fuel economy during full or split engine operation but which jets may be bypassed during engine load conditions requiring additional enrichment of the fuel-air mixture.

Other objects and advantages will be apparent from a perusal of the detailed description which follows.

In the drawings: 7

Figure 1 is a diag-ammatic representation of a fuel system embodying the subject invention;

Figure 2 represents a mechanism combining the subject invention with the fuel cut-off valve;

Figure 3 is a view along line 33 of Figure 2; and

Figure 4 is a view along line 44 of Figure 2.

Referring to the drawings, a manifold is indicated generallyat 10 and is of the divided header type in which individual air induction passages 12 and 14 are adapted respectively to supply air to four of the engine cylinders through individual cylinder intake passages 16 and 18. Throttle valves 20 and 22 are disposed in each of the induction passages as are contoured diffusers 24 and 26. The diffusers and induction passages respectively coact to define venturis 25 and 27. Fuel. nozzles 28 and 29 are disposed in the individual cylinder intake passages and are adapted to supply fuel to cylinders 30 when the cylinder intake valves 32 are open. 7

In the present control system, as in the aforenoted copending application, a group of cylinders and associated air intakes are always active whereas the remaining cylinders are normally inactive with the latter being activated only after the engine load exceeds a given value. In the present illustration, intake 12, throttle 20 and the four associated cylinder intake passages 16 are the active part of the system'whereas intake 14, throttle 22 and intake passages 18 constitute the normally inactive part of the system.

Fuel is adapted to be supplied to the nozzles 2829 through a fuel injection metering device indicated generally at 34 which is shown and described in detail in copending application Serial No. 608,853, Dolza, filed September 10, 1956, now Patent No. 2,845,098. The fuel metering system functions'in the same manner as described in the aforenoted copending application and does not, per se, constitute a part of the present invention.

Air is drawn in through both induction passages as already noted. However, only the active induction pastake induction passages are utilized in the subject split.

engine, it is possible for venturi 25 to be reduced sufficiently in size such that one-half engine operation will produce the same metering signal in piezometer ring .36

The

as total engine air flow would produce on the single venturi used in the aforenoted Dolza application Serial No. 608,853. Further, since venturi depression in piezometer ring 36 is proportional to the nozzle pressure drop across all of the nozzles 28 and with equal air flow restriction in each induction passage, due to coordinated (equal opening) positioning of the throttles, the venturi signal may be taken off from the active induction passage during all operating conditions.

Fuel control mechanism 34 is adapted to supply fuel pressure to conduit 42 in proportion to mass air flow. A branch conduit 44 is supplied from conduit 42. Conduits 42 and 44 respectively lead to distributors 46 and 48 which in turn supply the active and inactive nozzles through individual conduits 50 and 52.

Throttles 20 and 22 are interconnected through a linkage mechanism indicated generally at 54 for synchronized operation by the operator through the actuation of an accelerator pedal 56. Accelerator controlled linkage operation is, however, modified by other mechanisms to be subsequently described.

The accelerator pedal controlled linkage 54 includes an arm 58 fixed to the active throttle shaft 60. Arm 58 is articulated through a link 62 to a double articulated lever 64. The upper portion 66 of lever 64 is articulated intermediate its ends to a link 68 connected at its other end to accelerator pedal 56. The lower end of lever portion 66 is articulated at 70 to member 72 of the lever 64. The lower end of member 72 is pivotally mounted on a fixed support 74.

The pivotal connection 70 between lever portons 66 and 70 has a link 76 articulated thereto and the other end of which link is connected to a rod '78 of a servo device indicated generally at 80. Servo device 80 includes a pair of casing members 82 and 84 which pe ripherally clamp a flexible diaphragm 86 therebetween. Rod 78 is centrally fixed to the diaphragm and extends through an opening 88 in casing 84. A spring 89 is disposed in servo chamber 90 and tends to bias diaphragm 86 to the right. It is possible, however, to eliminate spring 89 if desired.

The upper end of lever 64 has a spring 92 connected thereto, the other end of. which is grounded at 94. Assuming for the moment that all other control forces remain unchanged, it is apparent that as the accelerator pedal 56 is depressed the throttle linkage system is such that the active throttle 20 will be opened. noted at this point that the pivoted connection 70 between members 66 and 72 of double articulated lever 64 may be pivoted between two positions by servo mechanism 80 in conjunction with spring 89. 'When, as is the case during eight cylinder operation, the vacuum forces on either side of diaphragm 86 are substantially balanced, spring 89, through rod 78 and link 76, will shift pivoted connection point 70 in a rightward direction as shown in the drawing. This action causes a counterclockwise rotation of member 66 moving throttle 20 in a closing direction. As will be subsequently considered in greater detail when the vacuum in chamber 90 overcomes spring 89 the parts will be shifted to the dotted line positions to open throttle 20. As will subsequently be more apparent, this differential movement of the active throttle 20 is for the purpose of readjusting the throttle position to facilitate a smooth transition between four and eight cylinder operation.

Active throttle lever 58 is articulated through a link 96 to an arm 98 loosely mounted on the inactive throttle valve shaft 160 so that the actuation of the active throttle may or may not affect similar movement of the inactive throttle 22 depending on the actuation of other devices which will be subsequently considered. A lever 10.2 is fixed to the inactive throttle shaft 106 and includes a tab portion 104 adapted to engage with the loosely mounted lever 98. Assuming the system control forces are such that the inactive throttle 22 is in a closed position, as

It should be.

shown, then the levers 98 and 102 are in operative engagement and opening movement of the active throttle 20 will likewise open the inactive throttle.

The various devices utilized to vary the subject fuel system between split and full operation will now be considered. In general, it has been found that as long as the manifold vacuum in the active portion 106 of manifold 10 is above a predetermined value, e.g. four inches of mercury, most economical engine operation will be achieved by split or four cylinder operation of the engine with the remaining cylinders being inactivated.

As already noted, in order to prevent pumping losses in the inactive engine cylinder it is desired to fully open inactive throttle 22 during split engine operation. This full opening movement of throttle 22 is achieved by a servo mechanism 110 which includes a pair of easing members 112 and 11 4 peripherally clamping a diaphragm 1'16 therebetween. A control rod 118 is centrally fixed to diaphragm 116 and projects through an opening 120 in the casing 112 and is connected to link 122 articulated to lever 102. A spring 124 disposed in chamber 125 between diaphragm 116 and casing 114 normally urges the lever 102 and throttle 22 in a counterclockwise or closing direction and under which condition, as noted, tab 104 of lever 102 is in engagement with active throttle controlled lever 98.

The actuation of servo 110 is under the control of a shift valve device indicated generally at 126. Device 126 includes a plurality of easing members 128, 130 and 132. Casing 132 includes a ported cylindrical opening within which a spool type valve member 134 is slidably disposed. Valve member 134 includes a stem 136 extend'ng toward casings 128 and 130 and upon which a pair of flexible diaphragms 138 and 140 are centrally mounted. The first diaphragm 138 is peripherally clamped between casings 128 and 130 while the second and smaller diaphragm 140 is peripherally clamped by the casings 130 and 132. Chamber 142 defined by casing 128 and diaphragm 138 is connected through a passage 144 with the active manifold 106 whereby active manifold vacuum is at all times transmitted to the chamber.

Chamber 146 defined by diaphragms 138 and 140 and casing 130 is communicated through a conduit 148 with the inactive manifold 150 and likewise is at all times subject to the vacuum force extant therein. A spring 152 isalso disposed in vacuum chamber 142 and biases spindle valve 134 in a rightward direction which, other control forces permitting, causes conduits 154 communicating with chamber 125 of servo 110 to be exhausted to the atmosphere through an exhaust port 158 in casing 132. In such case spring 124 would move inactive throttle '22 inathrottle closing direction.

So long as the vacuum in manifold; 106 exceeds that in manifold 150 by a differential of four inches of mercury, the vacuum force in chamber 142 will be sufliciently strong to overcome spring 152 as well as the vacuum force in chamber 146 to shift valve 134 to the left. Under this circumstance active manifold vacuum from conduit 160 will be admitted from valve casing port 162 between the lands of valve 134 where it will act through conduit 154 on inactive throttle diaphragm 116 to shift the diaphragm to theright against the force of spring 124 to fully open the inactive throttle.

At thesame timethe vacuum forces from manifolds 1G6 and 150 are respectivelytransmitted through conduits 164 and 166 to chambers 9 0and 91 of accelerator control linlgageservo80. The same vacuum'difierential will cause diaphragm $6 of servo 8 0 to be shifted to the left moving the pivotal connection 70 to itsleftmost position in which-a stop 168-011 member 72 of lever 64 abuts a fixed step 170. Theleftward movement of pivotal con;

' traction-70 causes member 66; of lever 64 .tobe rotated in a clockwise direction increasing the opening .of the active g Lever 66 continues to pivot the active throttle 20 is opened to a greater extent than during corresponding eight .cylinder operation.

Contemporaneously with the shifting of the throttle linkage and the opening of the inactive throttle, a servo valve device 172 is adapted to cut off .the flowof fuel to the inactive nozzle distributor48. Servo valve device 172 includes a pair of casing .members 174 and 176 peripherally clamping a diaphragm 178 therebetween and thereby forming a pair of vacuum chambers 180 and 182. Vacuum chambers 180 and 182 in turn communicate through conduits 184 and 186 with active and inactive manifold vacuum conduits 144 and 148. A control rod 188 is centrally fixed to diaphragm 178 and terminates in a valve portion 190 which, when the predetermined vacuum differential exists between manifolds 106 and 150, is shifted to the right against the force of spring 192 to cut off the flow of fuel from conduit '44 to nozzles 29.

The transition from split or four cylinder operation to eight or full engine operation is, as noted, affected when the vacuum in the manifold 106 drops below a;predetermined value, e.g., four inches of mercury. When this about point 70 although,

happens the force of spring 152 acting on the shift valve device diaphragm 138 will cause valve 134 to be moved to the right atmospherically venting inactive throttle servo chamber 125 and causing the spring 124 to, move the inactive throttle towards a closed position and operatively engaging inactive throttle levers 102 and 98 whereby synchronized operation of the throttles will thereafter take place.

Closing the inactive throttle substantially equalizes the vacuum in manifolds 106 and 150 under which conditions the vacuum forces on either side of linkage controlling servo diaphragm 86 will be substantially equal and spring 89 will shift the active throttle 20 to a more closed position, supra. Again, the equal vacuum in manifolds 106 and 150 will be transmitted to fuel cut-off valve servo chambers 180 and 182 permitting spring 192 to open valve 190 and thereby initiating fuel flow to inactive nozzles 29.

During eight or full cylinder operation the active and inactive manifold vacuums are equal resulting in no vacuum force differential acting on shift valve diaphragm 138. However, when the vacuum in chamber 146 of the shift valve device 126 exceeds a given value, e.g. 15 inches of mercury, it will act on the small diaphragm 140 with sufiicient force to overcome spring 152 and shift the valve 134 to the left. This again fully opens the inactive throttle which once again causes the servos 80 and 172 to again adjust the throttle valves and fuel flow to four cylinder operation.

As noted, supra, fuel metering device 34 is generally the same as that shown and described in copending application Serial No. 608,853 Dolza, however, it differs in one important respect when combined with'the instant split engine fuel system. In the Dolza metering device economy or power fuel fiow is controlled by providing an adjustable fulcrum mechanism which, in effect, decreased the rate of fuel flow during normal or light engine load conditions and increased the same during heavy load conditions. In addition to being complicated and hence costly, the adjustable fulcrum system introduces an undesirable hysteresis factor which adversely affects the metering control.

The present invention substitutes an improved system for achieving economy and power fuel flow and which system is compatible with split engine operation.

Referring first to Figure 1, a jet or orifice system indicated generally at 270 is interposed between metered fuel supply conduit 42 and inactive and active nozzle supply conduits 44 and 50. System 270 includes a plurality of parallel flow related conduits 272, 274 and 276 disposed between conduits 44 and 50.

A servo controlled valve 278 is associated with conduit 6 t 272. Valve 278 includescasings 280 and 282 having a diaphragm 284 peripherally clamped therebetween. A valve element 286 is centrally secured to, diaphragm 284 and projects within conduit 272 to control fuel flow therethrough. A spring element 288 disposed between casing 280 and diaphragm 284 biases the diaphragm in,

a direction tending to open valve element 286. Chamber 290 defined by casing 280 and diaphragm284 is connected by conduit 292 with the active manifold vacuum passage 144. Thus when the active manifold vacuum is above a predetermined value, indicative of an ability of the engine to run on an economy fuel-air mixture, the vacuum in chamber 290 will overcome spring 288 closing valve element 286iblocking fuel flow through conduit 272.

With conduit 272 blocked by valve element 286, fuel from supply conduit 42 flows through conduits 294 and 274. Conduit 294'connects with-inactive nozzle supply conduit 44 while conduit 274 connects with conduit 296 supplying active fuel nozzle distributor .46.

- Jets or orifices 298 and 300 are respectively disposed in conduits 294 and 274 to restrict the flow therethrough.

Thus with conduit 272 blocked, the flow of fuel to the active and inactive nozzles is restricted by economy jets 300 and 298. In this way an economy or lean fuel-air mixture is supplied to the nozzles during normal or light load conditions.

. During heavy load conditions, diminished vacuum in chamber 290 will permit spring 288 to open element 286 in which event fuel will flow through conduit 272 to conduits 296 and 276 to supply the active and inactive nozzles with increased fuel ;for power" operation. During split engine operatipn, fuelcut-oif valve 172 will stop fuel flow to the inactive nozzles 29. Since the fuel flow through the inactive economy jet 298 is stopped, there will be no pressure drop across the jet. However, the continued fuel flow through the active economy jet 300 will cause a reduced pressure to the active nozzles 28. Normally, the higher pressure downstream of the inactive jet 298 would cause reverse fuel to flow through conduit 276 and would raise the pressure to the active nozzles undesirably enriching the fuel mixture. To prevent such reverse fiow a check valve 302 is disposed in conduit 276 which blocks flow from conduit 294 directly to conduit 296 via conduit 276.

Figures 3 and 4 show a valve body 310 embodying fuel cut-off valve 172 and jet system 270. The numerals of the various components in body 310 are the same-as in Figure 1 and the operation of the components is as already described.

It is apparent that the subject invention has been diagrammatically represented in order to simplify the understanding of its operation. It is also apparent that the substance of the subject invention may be embodied in various structural arrangements within the intended scope of the hereinafter appended claims.

I claim:

tion engine comprising a source of fuel metered in accordance with certain engine operating conditions, an

intake manifold, a plurality of intake passages communicating said manifold with the individual engine cylinders, a fuel nozzle disposed in each cylinder intake passage conduit means connecting said nozzles with said fuel source, said conduit means including a pair of parallel flow paths, orifice means in one of said flow paths, the other fiow path being unrestricted, and a valve device disposed within said conduit means, said device including a diaphragm, a valve element fixed to said diaphragm, a spring normally biasing the valve element to a position permitting flow through the unrestricted flow path, and conduit means communicating said manifold and said diaphragm whereby when manifold vacuum exceeds a predetermined value it will overcome the spring force to cause the valve element to block flow through the unrestricted flow path.

2. A charge forming device'for an internal combustion engine comprising afir'stair induction system for supplying'air to certain cylinders of the engine, a second air induction system for supplying air to the remaining engine cylinders, first and second throttle valves for respectively controllingthe flow of air through said first and second systems, means for supplying fuel to each of said air induction systems in accordance with engine demand, said each fuel supplying means including means restricting fuel flow to the associated nozzles under normal engine load conditions, and engine load responsive means adapted to bypass said flow restricting means to permit full fuel flow during high engine load conditions, means for synchronizing the actuation of said throttles, means responsive to the engine vacuum difierentia'l in said air induction systems posteriorly of said throttles for fully opening one of said throttles when said differential exceeds a'predetermined value, additional means responsive to said predetermined vacuum differential for moving the other throttle to a more open position when said one throttle is fully opened, and further means operable in response to said predetermined vacuum differential to cut off the flow of fuel to the air induction system associated with the fully opened throttle.

3. A charge forming device for an internal combustion engine comprising a first air induction system for supplying air to certain cylinders of the engine, a second'air induction system for supplying air to the remaining engine cylinders, first and second throttle valves for respectively controlling the flow of air through said first and second systems, means for supplying fuel'to each of opening one of .saidthrottles when said differential ex?- ceeds a predetermined value, additional means responsive to said predetermined vacuum difierential for moving the other throttle to a more open position when said one throttle is fully opened, and further means operable in response to said predetermined vacuum differential to cut off the flow of fuel to the air induction system associated with the fully opened throttle, and valve means for pre venting fuel flow from the means normally supplying fuel to the latter induction system to the other induction system when said fuel flow is cut off.

4. A'charge forming device as set forth in claim 2 in which each fuel supplying means includes a pair of parallel flow paths, one of each pair of parallel flow paths including'an orifice therein, the other of each pair of flow paths being unrestricted, said engine load responsive means blocking flow through the unrestricted flow paths during normal engine load operation.

'RefereucesCited in the file of this patent UNITED STATES PATENTS 2,422,808 Stokes June 24, 1947 

